1. Field of the Invention
The invention relates to a screwdriver, more particularly to one with four usable wrench units.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional modular screwdriver 1 is shown to include an elongated hollow handle 11, a plurality of bits 15,16, a first sleeve 12, a second sleeve 13, and a connecting rod 14. The handle 11 has a hexagonal-cross-sectioned central bore 111 formed therethrough. The first sleeve 12 has a central bore 121 that is formed therethrough and that has a hexagonal cross-section. The second sleeve 13 has a central bore 131 that is formed therethrough and that has a hexagonal cross-section of a different size from the central bore 121 in the first sleeve 12. The connecting rod 14 extends axially and movably through the handle 11, and has first and second end portions 14',14" that extend respectively into the first and second sleeves 12,13. Each of the first and second end portions 14',14" of the connecting rod 14 has an end surface that is formed with a hexagonal-cross-sectioned bore 143,144. One of the bits 15,16 is disposed removably on the connecting rod 14. The first sleeve 12 is formed with an annular retaining slot 122. The first end portion 14' of the connecting rod 14 is formed with an annular first positioning groove 141 and an annular second positioning groove 142. The first positioning groove 141 is nearer to the second end portion 14" of the connecting rod 14 than the second positioning groove 142. A clip 123 extends through the retaining slot 122' and engages one of the first and second positioning grooves 141,142. Moreover, the connecting rod 14 is further formed with a hexagonal-cross-sectioned positioning portion 145 to engage fittingly in the central bore 111 in the handle 11.
Referring to FIG. 1, when the connecting rod 14 is located at a first position, the first end portion 14' extends through the first sleeve 12 so as to receive the bit 15 for functioning as a screwdriver to drive screws. The second end portion 14" extends into a middle portion of the second sleeve 13 so that the second sleeve 13 functions as a wrench.
Referring to FIG. 2, when the connecting rod 14 is located at a second position, the second portion 14" extends through the second sleeve 13 so as to receive the bit 16 for functioning as a screwdriver to drive screws. The first end portion 14' extends into an intermediate portion of the first sleeve 12 so that the first sleeve 12 functions as a wrench.
Accordingly, the conventional modular screwdriver can only provide two usable wrench units, thereby, resulting in limited usage thereof.